menstrual cycle

• STAGE 1

  lasts 4 days. breaking down of the uterus lining.
• STAGE 2

  lasts 10 days. lining builds back up again into a thick spongy layer to prepare for the fertilised egg.
• STAGE 3

  lasts one day (day 14). egg is released from the ovaries.
• STAGE 4

  Lasts 14 days. Maintenance of the uterus lining. If the egg is not fertilised the uterus lining will begin to break down again.
• OESTROGEN

  stimulates growth of uterus lining
• PROGESTERONE

  maintains the uterus lining, when levels drop lining breaks down.
• LH

  luteinising hormone. Stimulates release of egg (ovulation)
• FSH 


  follicle stimulating hormone. Causes egg to mature.
• Oestrogen is stimulated by

  FSH
• FSH is inhibited by

  oestrogen
• LH is stimulated by

  oestrogen
• LH is inhibited by

  progesterone
• FSH is inhibited by

  progesterone